US1772415A - Device for testing relative frictional characteristics of materials - Google Patents

Description

1,772,415 DEvI'cE Fon TESTING RELATIVE FRIoTIoNAL cHARAcTERIsTIUs or'uATRIALs ug. 5, 1930. E. CARPENTER Filed sept. 1v, ll1927 2 Sheets-Sheet 1 Aug. 5,y 1930. E. CARPENTERA DEVICE yFOR TESTING RELATIVE FRICTINAL CHARACTERISTICS OP IATERIALS Filed Sept. 1'7, 1927 2 Sheets-Sheet 2 2 in degrees, or may be based on an arbitrarily selected unit.

The test specimens, see F ig. 4, which may be in the form of flat rectangular pieces 28 of the materials t0 be tested preferably occuplyv a correspondingly shapedlreeess 29 1n underside of weight elements 31. These weight elementsn. the present instance are Y provided with a passage 321111 which is mounted a bolt 33. "The ends'of'tlie"'passage 32 respectively at the upper and lower surface of the block 31` are countersunk to provide in one instance a recess for receptionofV nuts 34l Vwhich hold the bolt place, and in the'other instance for reception of a spring 35 Conon.v thepouter projecting ends of which are pivotally mounted the side links 38 offa mem'- ber comprising these side links, together with connecting rods 39, 41, vwhichjointhe cor.- responding ends of the links together'. 'The connecting rod 39 of this vmember is-so positioned as to occupy a position overlying the tops of the blocks31 when the latter'are at 4the top ofthe inclined planepan'd'springs'@ `connected to the side pieces 11 and 12 andto the: forward ends of the links 38 resiliently hold the connecting rod v39 againstthe tops of the blocks 31, as shown 'Figli Stops 43are`provided for the links 38 `whichlinriit the downward movement of'V the forward ends vof the links, and when they blocks 31 are withdrawn hold the forward ends of thelinks in a positionsuchthat the lowered-ge ofthe connecting rod- 39 stillioccupies a posi-tion sub,- stantially in the plane occupied the upper surfaces of the blocks 31-When the latter' are 'at the'upper end of the member 2.'v Y f Y 2 As indicated in'Fig. 4, theconnectingrod v v'39* functions, to retain the blocks 31 at the upper. Oendfof theinclined plane byengaging the; projectinghlds 36 f the boltsi', 'and thev bolts are preferably. ,so-'placed `in the Y blocks, that the forwardedges of the latter# .'i'vlien retained as described lie, on a line lwith the4 Zr0, or initial. mark of thefcales on the ASide niiesll]am?!VK 12 es Shows '11.1 g- 1- n ldepressing theconnecting rod- 4 1Y at the rear. end. l0i the links 381th@ AC01in"fiilared 3.9.: will be elevated tof release the bleeks- 31 vvardly on the planey sufficiently; far to Vbring the heads of theV bolts 36above the position of the'rodf39, tohave the blocks automatically'retained atV the upper end'of f the plane until the rod 39 is elevated as described above.

On the base plate l and at the bottom of the member 2 is a stop element 44 against which the blocks 31 impinge as they approach the bottom *off the plane.

. It is obvious that the material of which the member 2 sfmade will affect the action 0f the VVtest specimens on the plane. Where the 'deviceis' usedto test leather belting it is desirable-to form the surface` on Whichthe blocks slide of material or materials of which pulleys are rcommonly frmed'and' to'have the surface conform as closely as possible in physical characteristics to the pulley surface. There is to be no limitation as to thephysical characteristics of the surface of the member 2 on which-the blocks slide.

Preferably the ways 6, 7, and 8 are made of such VWidth that there. is no likelihood under normal conditions of the `blocks coming inlcontact with the partition elements as theyslidedown the plane. In the other instances'it may. be desirable tor so form .the partition elements or. the blocks that if contact is made the area. thereof shall be a minimum. A l f l Y The operation of the device will,v be apparent from the foregoing description.l With the different test 'specimens 28 occupying the recesses in'fthe under faces of theblocks 31 `and the member 2 elevatedV to the desired inclination, release ofthe blocks 31 asfdescribed permits.themtoy move down the plane, and the dierent rates of movement of the blocks, or the time required to.- pass down the `plane will aord an'accurateindieation ofthe frictional f characteristics of the respective; test specimens; or the. plane may be lowered by manipulationi of the hand wheel 18,. and lwith the testspecimensin position at the; upper fend `ofthe plane, the llatter ymay be gradually elevated; note beingy ymade. of the respective angulanpositions. of the members 2 `atp which :the differenti. specimens start moving down the planet In this-instance, of: course, .it will Vvbe necessary. to'. render inoperative4 the `blockretaining means; at. thewtop of the plane so that thespecimensarefree to move downthe plaine when the inclination is such that, the frictional resistance of the specimen is` over` fcone. The respective inclinations; of` the plane at. which the diiferent specimensprstart moving down t-he planeafford a furtherco'm- .parativ'eftest `of thee frictional characteristics ofv the said* specimens. Obviously the` device affords a 'meansA fork 'testing theV frictional l A Y inertia ofi materials, that 'is the frictional re- :which are thenpernutted to movev dorm the inclined plane." Thearrangementais suclrthat it is -onlywneces'sary to slide.l the, blocks; up-

sistance': opposing'finiti'a'l movement when the body isy atrest, sometimes: called' static fric- I a friction-testing machine, the com-l bination with a base,of lamember pivotallyy l'lU secured at one end to the base and constituting an adjustable inclined plane,` partition elements dividing the plane into a plurality Y v of separate Ways7 means for vertically adjustof said pivot lying in the plane of the "upper surface of said member, a specimen-holding block slidable on the said upper surface of said member, means for vertically adjusting l the free end of said plane member, andy a relatively fixed member on the base grad-VA uated and adapted to cooperate with the said pivoted member to give an indication of the inclination thereof in any adjusted position.

CHAS. E. CARPENTER.

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